title: Alterations of white matter integrity related to the season of birth in schizophrenia: a DTI study.
abstract: In schizophrenia there is a consistent epidemiological finding of a birth excess in winter and spring. Season of birth is thought to act as a proxy indicator for harmful environmental factors during foetal maturation. There is evidence that prenatal exposure to harmful environmental factors may trigger pathologic processes in the neurodevelopment, which subsequently increase the risk of schizophrenia. Since brain white matter alterations have repeatedly been found in schizophrenia, the objective of this study was to investigate whether white matter integrity was related to the season of birth in patients with schizophrenia. Thirty-four patients with schizophrenia and 33 healthy controls underwent diffusion tensor imaging. Differences in the fractional anisotropy maps of schizophrenia patients and healthy controls born in different seasons were analysed with tract-based spatial statistics. A significant main effect of season of birth and an interaction of group and season of birth showed that patients born in summer had significantly lower fractional anisotropy in widespread white matter regions than those born in the remainder of the year. Additionally, later age of schizophrenia onset was found in patients born in winter months. The current findings indicate a relationship of season of birth and white matter alterations in schizophrenia and consequently support the neurodevelopmental hypothesis of early pathological mechanisms in schizophrenia.
authors.affiliation: Department of Psychiatric Neurophysiology, University Hospital of Psychiatry, University of Bern, Bern, Switzerland.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Giezendanner
authors.forename: Sebastian
authors.initials: S
authors.lastname: Walther
authors.forename: Nadja
authors.initials: N
authors.lastname: Razavi
authors.forename: Claudia
authors.initials: C
authors.lastname: Van Swam
authors.forename: Melanie Sarah
authors.initials: MS
authors.lastname: Fisler
authors.forename: Leila Maria
authors.initials: LM
authors.lastname: Soravia
authors.forename: Jennifer
authors.initials: J
authors.lastname: Andreotti
authors.forename: Simon
authors.initials: S
authors.lastname: Schwab
authors.forename: Kay
authors.initials: K
authors.lastname: Jann
authors.forename: Roland
authors.initials: R
authors.lastname: Wiest
authors.forename: Helge
authors.initials: H
authors.lastname: Horn
authors.forename: Thomas Jörg
authors.initials: TJ
authors.lastname: Müller
authors.forename: Thomas
authors.initials: T
authors.lastname: Dierks
authors.forename: Andrea
authors.initials: A
authors.lastname: Federspiel
mesh_terms: D000328:Adult; D000368:Aged; D016880:Anisotropy; D001369:Axons / Q000473:pathology*; D001921:Brain / Q000473:pathology; D001931:Brain Mapping / Q000379:methods; D016022:Case-Control Studies; D056324:Diffusion Tensor Imaging / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D036801:Parturition / Q000502:physiology*; D012307:Risk Factors; D012559:Schizophrenia / Q000209:etiology* / Q000473:pathology*; D012621:Seasons; D055815:Young Adult